The present invention relates to a stapler used to staple a stack of paper discharged from an image forming device such as a photocopier or a printer.
The following is an explanation of the stapling operation of a prior art stapler with reference to FIG. 1 and FIG. 2. The sheet of staples S shown in FIG. 1 consists of a series of single staples. The sheet of staples S is rolled up and housed in the housing unit 50a of the cartridge 50. Here, the sheet of staples S extends from the extraction opening 50b in the housing unit 50a. The cartridge 50 mounted in the housing unit 50a has a pair of walls 50c, 50c separated at a specific interval as an extension of the extraction opening 50b. The interval between the walls 50c, 50c is roughly equal to the width of the sheet of staples S. Therefore, the sheet of staples S extending from the extraction opening 50b passes between the walls 50c, 50c in the direction of the arrow shown in FIG. 1.
Guides 51, 51 are placed on the cartridge 50 to prevent the sheet of staples S from riding up from the extraction opening 50b. In other words, the sheet of staples S is restrained widthwise by wall 100c and prevented from riding up by the guides 51, 51 so as to travel in the direction of the arrow. As shown in FIG. 1, a plate 52 is extended between the side walls 50c, 50c, and a reverse motion stopping tab 52a is formed on both ends of the plate 52. The reverse motion stopping tab 52a makes contact with the sheet of staples S to prevent the sheet of staples S from moving in the direction opposite to the arrow back into the housing unit 50a. In other words, the sheet of staples S moves in the direction of the arrow shown in FIG. 1, and is not allowed to return to the housing unit 50a. 
The cartridge 50 is mounted in the main body of the device 70 shown in FIG. 2, and the pressure unit 53 formed in the cartridge 50 is brought to bear when the cartridge is mounted on the spring plate 55 on the advancing unit 54 of the main body of the device 70. The pressure from the spring plate 55 keeps the advancing unit 54 in the position shown in FIG. 2. When the driver 56 applying the staples is lowered from the position shown in FIG. 2, the protrusion 56a on the driver 56 is brought to bear on the protruding plate 54a formed on the advancing unit 54. Therefore, the lowering force of the driver 56 is communicated to the advancing unit 54 via the protrusion 56a and the protruding plate 54a, and the advancing unit 54 resists the spring action of the spring plate 55 and is rotated counterclockwise in the drawing. When the advancing unit 54 has traveled a full stroke, the protrusion 56a passes the position of the protruding plate 54a. When the protrusion 56a passes the position of the protruding plate 54a, the advancing unit 54 becomes free, and the advancing unit 54 subjected to the force of the spring 55 returns to its original position as shown in the figure.
An advancing tab 57 is located on the advancing unit 54. This advancing tab 57 makes elastic contact with the sheet of staples S extending from the cartridge 50. Therefore, the rotation of the advancing unit 54 causes the advancing tab 57 to advance the sheet of staples S in the direction of the driver 56. When the advancing unit 54 rotates counterclockwise, the advancing tab 57 makes and maintains elastic contact with the sheet of staples S. When the advancing unit 54 rotates counterclockwise, force is applied to return the sheet of staples S. However, the reverse motion stopping tab 52a prevents the sheet of staples from returning.
Often several cartridges are provided containing rolled sheets of staples of varying lengths. These cartridges can be replaced to provide the desired type of staples.
When a cartridge 50 is replaced in a stapler, the cartridge 50 is removed with the advancing tab 57 bearing down on the sheet of staples S. When a cartridge 50 is removed with the advancing tab 57 bearing down on the sheet of staples S, the sheet of staples S is pulled out from the cartridge 50. Because the revere movement stopping tab 52 bears down on the pulled out sheet of staples S, the staples do not return to their original position. As a result, some of the staples in the sheet of staples S are wasted.
Sometimes the cartridge 50 is divided in two and only the sheet of staples in the housing unit is replaced. However, even though the cartridge 50 is divided in two, the reverse motion stopping tab 52a continues to function and the section of the sheet of staples S drawn out by the reverse motion stopping tab 52a does not return to its original position. As a result, the section of the sheet of staples is wasted.
Therefore, there remains a need for a stapler that does not waste any staples when a staple cartridge or sheet of staples is replaced.
One embodiment of the invention relates to a stapler having a sheet of staples, a detachable cartridge for housing the sheet of staples and a driver mechanism for driving a staple withdrawn from the cartridge into a stack of paper. The main body of the device has a reverse motion stopping mechanism to prevent the sheet of staples from moving back into the cartridge, and the reverse motion stopping mechanism makes contact with the sheet of staples and the reverse motion stopping mechanism releases contact with the sheet of staples when the operating unit is operated.
Another embodiment of the invention relates to a stapler including a detachable cartridge for housing the sheet of staples and a driver mechanism for driving a staple withdrawn from the cartridge into a stack of paper. The mounting unit has a reverse motion stopping mechanism to prevent the sheet of staples from moving back into the cartridge, and the reverse motion stopping mechanism makes contact with the sheet of staples when the mounting unit is installed and the reverse motion stopping mechanism releases contact with the sheet of staples when the mounting unit is removed.
In yet another embodiment, the reverse motion stopping mechanism is a rotating unit such as a tab, a roller or an endless belt.
Another embodiment relates to a stapler including, a detachable cartridge for housing a sheet of staples and a driver mechanism for driving a staple withdrawn from the cartridge into a stack of paper. The mounting unit has an advancing mechanism for advancing the sheet of staples in the direction of the driver mechanism and a reverse motion stopping mechanism to prevent the sheet of staples from moving back into the cartridge. The advancing mechanism and the reverse motion stopping mechanism make contact with the sheet of staples when the mounting unit is installed and the advancing mechanism and the reverse motion stopping mechanism release contact with the sheet of staples when the mounting unit is removed.
The present invention is also directed to a stapler, where the mounting unit is equipped with an advancing mechanism casing constituting the advancing mechanism and a housing space for housing the advancing mechanism casing. The advancing mechanism casing is configured to move up and down inside the housing space. Spring action is applied to the advancing mechanism casing and the spring action normally extends upward from the housing space. The advancing mechanism and the reverse motion stopping mechanism are released from the sheet of staples in the extended state, and the advancing mechanism and the reverse motion stopping mechanism make contact with the sheet of staples when the advancing mechanism and the reverse motion stopping mechanism resist the spring action.
Another embodiment relates to a stapler, where the advancing mechanism is equipped with a shaft, a rotating unit rotating around the shaft, an moving plate engaged with the rotating unit and reciprocating as the rotating unit rotates, and an advancing tab mounted on the moving plate. The rotating unit rotates with the movement of the driver shaft supporting the driver mechanism.
The present invention is also directed to a stapler, where the advancing mechanism and the reverse motion stopping mechanism are rotating units such as a tab, a roller or an endless belt.
Another embodiment is stapler including a detachable cartridge for housing a sheet of staples and a driver mechanism for driving a staple withdrawn from the cartridge into a stack of paper. The main body of the device has an advancing mechanism for advancing the sheet of staples in the direction of the driver mechanism. The advancing mechanism has a reverse motion stopping mechanism, and the advancing mechanism and the reverse motion stopping mechanism make contact with the sheet of staples and release contact with the sheet of staples when the operating unit is operated.
Another embodiment also relates a stapler including a detachable cartridge for housing a sheet of staples, a driver mechanism designed and configured to drive a staple withdrawn from the cartridge into a stack of paper; and a mounting unit attached to the detachable cartridge. The mounting unit include a reverse motion stopping mechanism to prevent the sheet of staples from moving back into the cartridge, an advancing mechanism casing and a locking mechanism. The advancing mechanism casing has an advancing mechanism for advancing the sheet of staples in the direction of the driver mechanism and a housing space for housing the advancing mechanism casing. The advancing mechanism casing is configured to move from an up position to a down position inside the housing space and the locking mechanism locks the advancing mechanism casing in the down position. The advancing mechanism and the reverse motion stopping mechanism make contact with the sheet of staples and release contact with the sheet of staples when the stapler is operated.